Is the public more likely to forgive a person for an unintentional killing if they show visible signs of suffering and regret?

The UK is making smoking illegal if you're born after 2008. Firstly, is it like "you can't get them", or more "if you ever touch one you're going to jail"? Secondly, why ban smoking but not alcohol, drugs, gambling and other "harmful" things.
What's the role of teachers or preachers in helping people find a balance between their ego and their vision of God?